Open surgery is still the standard technique for most surgical procedures. It has been used by the medical community for several decades and consists of performing the surgical tasks by a long incision in the abdomen or other body cavity, through which traditional surgical tools are inserted. However, due to the long incision, this approach is extremely invasive for the patient, resulting in substantial blood loss during the surgery and long and painful recovery periods in an in-patient setting.
In order to reduce the invasiveness of open surgery, laparoscopy, a minimally invasive technique, was developed. Instead of a single long incision, one or more smaller incisions are made in the patient through which long and thin surgical instruments and endoscopic cameras are inserted. Because of the low degree of invasiveness, laparoscopic techniques reduce blood loss and pain while also shortening hospital stays. When performed by experienced surgeons, these techniques can attain clinical outcomes similar to open surgery. However, despite the above-mentioned advantages, laparoscopy requires advanced surgical skills to manipulate the rigid and long instrumentation through small incisions in the patient.
Traditionally, laparoscopic instruments, such as graspers, dissectors, scissors and other tools, have been mounted on straight shafts. These shafts are inserted through small incisions into the patient's body and, because of that, their range of motion inside the body is reduced. The entry incision acts as a point of rotation, decreasing the freedom of the surgeon for positioning and orienting the instruments inside the patient. Therefore, due to the drawbacks of its instrumentation, laparoscopic procedures are mainly limited to use in simple surgeries, while only a small minority of surgeons is able to use them in complex procedures. Therefore, there has been a clear trend for providing distal articulations to end-effector elements of laparoscopic instruments, allowing the distal effector elements to be angulated with respect to the longitudinal axis of the instrument shaft.
Laparoscopic instruments can be provided as disposable or reusable medical devices. Disposable devices are thrown away after each utilization, without having the need to be cleaned. On the other hand, reusable devices must be cleaned and sterilized after each procedure. In many instances, cost-effectiveness and operating room efficiency requires that instruments be cleaned, sterilized and re-used.
Although techniques such as steam sterilization have been widely used, they are often insufficient to reach all of the blood and tissue residues that can enter a surgical instrument during a surgical procedure. In particular, for the case of instruments with articulated end-effectors (like the one disclosed in U.S. Pat. No. 7,819,894), the cleaning and sterilization processes are even more challenging. The higher mechanical complexity of the articulated end-effector brings additional places where tissue and blood can easily infiltrate. In addition, in order to be airtight and keep the body cavity inflated, these systems are constructed with an elongated and closed tubular body, from where the penetrated blood and tissue are very difficult to be removed.
Some reusable laparoscopic instruments (like to ones disclosed in EP1889579, U.S. Pat. Nos. 5,147,357, 5,304,203, 5,308,358, 5,368,606, 5,603,723 and US20090299141) can be disassembled for cleaning and thereafter reassembled for subsequent utilization. This enables access to the interior portions of the instrument tube and the internal mechanical elements housed therein, which results in more reliable cleaning and sterilization methods. However, this solution has only been used in instruments with low complexity end-effectors (mainly with a single distal degree of freedom), where the assembly and disassembly procedures are relatively simple and can therefore be easily accomplished by the hospital staff. This easy assembly/disassembly procedure cannot be applied to existing articulated instruments (like the one disclosed in U.S. Pat. No. 7,819,894). Indeed, in these instruments, the external tube of the instrument's shaft has the double function of giving structure to the instrument shaft and providing a sealing function for the instrument with respect to the trocar in order to preserve the inflation of the abdominal cavity where the instrument is operated. This limitation in the design of existing articulated instruments makes it impossible to remove the outer tube, which poses a significant challenge for the cleaning and sterilization of such instruments. Without being able to remove the outer tube, direct access to the internal elements of the articulated instrument is not possible, meaning that cleaning tools cannot be directly applied to the elements requiring cleaning, despite the fact that blood and tissue may have contaminated these elements during a surgical procedure. While some articulated instruments allow for the passage of a stream of water as a method of cleaning the internal elements, this does not provide for complete cleaning and is not an efficient solution.
Accordingly, an aim of the present invention is to overcome the aforementioned drawbacks of known devices by providing a new surgical instrument with an articulated end-effector, with uses in a cable-driven surgical instrument, where the external tube composing the instrument's shaft can be easily removed, for efficient cleaning, and subsequently reassembled for utilization.